Despite the fact that there have been significant developments in anti-cancer technology, such as radiotherapy, chemotherapy and hormone therapy, cancer still remains the second leading cause of death following heart disease in the United States. Most often, cancer is treated with chemotherapy utilizing highly potent drugs. In many cases, these chemotherapeutic agents show a dose responsive effect, and cell killing is proportional to drug dose. A highly aggressive style of dosing is thus necessary to eradicate neoplasms. However, high-dose chemotherapy is hindered by poor selectivity for cancer cells and severe toxicity to normal cells. This lack of tumor-specific treatment is one of the many hurdles that needs to be overcome by current chemotherapy.
One solution to current chemotherapy limitations would be to deliver an effective concentration of anti-cancer agents to utilize various pathways resulting in cancer cell death. For example, induction of DNA damage, increasing oxidant levels, increasing apoptosis, decreasing angiogenesis, inhibiting metastasis, and/or decreasing glycolysis using anti-cancer agents may be beneficial for patients.
Another approach to overcoming current chemotherapeutic limitations would be to deliver a combination of a tumor-targeted drug with one or more chemotherapeutic agents where the toxicity profile of the tumor-targeted drug and the chemotherapeutic agent are different. A further modification of this approach is to use the tumor-targeted drug and the chemotherapeutic agent in the combination treatment in amounts of each lower than typically used when the tumor-targeted drug or the chemotherapeutic agent is used alone for treatment.
Recent attention has been given to nitric oxide (NO) derivatives (NO-NSAIDs) for the treatment of cancer. The role of NO in cancer is complicated in that NO production can be mutagenic yet can affect apoptosis, proliferation, migration, adhesion, angiogenesis and vascular permeability. Often, low levels of NO may be pro-tumorigenic, while production of higher, sustained levels of NO can have cytostatic and cytotoxic effects on cancer cells. However, expression of the inducible isoform of NO synthase (iNOS) has been reported in malignancies of the breast, prostate, lung, brain and colon. Detection of increased iNOS levels also predicts poor survival in estrogen receptor α-negative (ER(−)) breast cancer patients. Thus, inhibition of iNOS within cancer cells may be therapeutic while delivery of exogenous NO may initiate tumor regression in simulation of the immune system. NO donors may lead to chemo- and radiosensitization and to overcome drug resistance by tumor cells.
Therefore, there exists a need for new methods that utilize various pathways resulting in cancer cell death. Accordingly, the present disclosure provides methods of using diazeniumdiolate-based prodrugs for treating cancer, which exhibit desirable properties and provide related advantages for modifying cancer cells.
The present disclosure provides methods utilizing the diazeniumdiolate-based prodrugs for the treatment of cancer via various mechanisms and procedures. The disclosure also provides kits comprising the diazeniumdiolate-based prodrugs.
Any of the embodiments described in the following clause list are considered to be part of the invention and are non-limiting:
1. A method of inducing DNA damage of a cell, said method comprising the step of administering a compound of the formula (I) or a pharmaceutically acceptable salt thereof:

wherein:
R1 is selected from C1-12 alkyl, C3-12 alkenyl, C3-12 alkynyl, C3-8 cycloalkyl, and heterocyclyl, each of which is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
R2 and R3 are the same or different and each is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino; and
R4 is —C(═O)R5, wherein R5 is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
or R4 is a non-steroidal anti-inflammatory drug (NSAID) moiety retaining its NSAID activity,
to the cell, wherein contacting the cell with the compound induces the DNA damage of the cell.
2. The method of clause 1, wherein the DNA damage comprises deamination of one or more base pairs in the cell.
3. The method of clause 1 or clause 2, wherein the DNA damage comprises cleavage of the DNA.
4. A method of binding to a thiol of a cellular protein, said method comprising the step of administering a compound of the formula (I) or a pharmaceutically acceptable salt thereof:

wherein:
R1 is selected from C1-12 alkyl, C3-12 alkenyl, C3-12 alkynyl, C3-8 cycloalkyl, and heterocyclyl, each of which is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
R2 and R3 are the same or different and each is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino; and
R4 is —C(═O)R5, wherein R5 is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
or R4 is a non-steroidal anti-inflammatory drug (NSAID) moiety retaining its NSAID activity,
to a cell comprising the cellular protein, wherein the compound binds to one or more thiols of the cellular protein.
5. The method of clause 4, wherein the binding is formed via HNO donation.
6. A method of increasing an oxidant level in a cell, said method comprising the step of administering a compound of the formula (I) or a pharmaceutically acceptable salt thereof:

wherein:
R1 is selected from C1-12 alkyl, C3-12 alkenyl, C3-12 alkynyl, C3-8 cycloalkyl, and heterocyclyl, each of which is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
R2 and R3 are the same or different and each is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino; and
R4 is —C(═O)R5, wherein R5 is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
or R4 is a non-steroidal anti-inflammatory drug (NSAID) moiety retaining its NSAID activity,
to the cell, wherein contacting the cell with the compound increases the oxidant level of the cell.
7. A method of increasing apoptosis of a population of cells, said method comprising the step of administering a compound of the formula (I) or a pharmaceutically acceptable salt thereof:

wherein:
R1 is selected from C1-12 alkyl, C3-12 alkenyl, C3-12 alkynyl, C3-8 cycloalkyl, and heterocyclyl, each of which is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
R2 and R3 are the same or different and each is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino; and
R4 is —C(═O)R5, wherein R5 is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
or R4 is a non-steroidal anti-inflammatory drug (NSAID) moiety retaining its NSAID activity,
to the population of cells, wherein contacting the compound with the population of cells increases the occurrence of apoptosis in the population of cells.
8. The method of clause 7, wherein the apoptosis occurs via a caspase signaling cascade.
9. The method of clause 8, wherein the caspase is caspase-3.
10. A method of decreasing angiogenesis in a population of cells, said method comprising the step of administering a compound of the formula (I) or a pharmaceutically acceptable salt thereof:

wherein:
R1 is selected from C1-12 alkyl, C3-12 alkenyl, C3-12 alkynyl, C3-8 cycloalkyl, and heterocyclyl, each of which is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
R2 and R3 are the same or different and each is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino; and
R4 is —C(═O)R5, wherein R5 is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
or R4 is a non-steroidal anti-inflammatory drug (NSAID) moiety retaining its NSAID activity,
to the population of cells, wherein contacting the compound with the population of cells decreases the occurrence of angiogenesis in the population of cells.
11. A method of inhibiting metastasis of a cell, said method comprising the step of administering a compound of the formula (I) or a pharmaceutically acceptable salt thereof:

wherein:
R1 is selected from C1-12 alkyl, C3-12 alkenyl, C3-12 alkynyl, C3-8 cycloalkyl, and heterocyclyl, each of which is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
R2 and R3 are the same or different and each is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino; and
R4 is —C(═O)R5, wherein R5 is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
or R4 is a non-steroidal anti-inflammatory drug (NSAID) moiety retaining its NSAID activity,
to the cell, wherein contacting the cell with the compound inhibits the metastasis of the cell.
12. A method of modifying a phenotype of a cell, said method comprising the step of contacting the cell with a compound of the formula (I) or a pharmaceutically acceptable salt thereof:

wherein:
R1 is selected from C1-12 alkyl, C3-12 alkenyl, C3-12 alkynyl, C3-8 cycloalkyl, and heterocyclyl, each of which is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
R2 and R3 are the same or different and each is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino; and
R4 is —C(═O)R5, wherein R5 is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
or R4 is a non-steroidal anti-inflammatory drug (NSAID) moiety retaining its NSAID activity,
to the cell, wherein contacting the cell with the compound modifies the phenotype of the cell.
13. The method of any one of clauses 1 to 12, wherein the cell is a cancer cell.
14. The method of clause 13, wherein the cancer cell is a proliferating cancer cell.
15. The method of clause 13 or clause 14, wherein the cancer cell is located in an oxygenated region of a tumor.
16. The method of clause 13 or clause 14, wherein the cancer cell is located in a non-oxygenated region of a tumor.
17. A method of decreasing glycolysis in a mammal, said method comprising the step of administering a compound of the formula (I) or a pharmaceutically acceptable salt thereof:

wherein:
R1 is selected from C1-12 alkyl, C3-12 alkenyl, C3-12 alkynyl, C3-8 cycloalkyl, and heterocyclyl, each of which is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
R2 and R3 are the same or different and each is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino; and
R4 is —C(═O)R5, wherein R5 is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
or R4 is a non-steroidal anti-inflammatory drug (NSAID) moiety retaining its NSAID activity,
to the mammal, wherein the compound of the formula (I) or pharmaceutically acceptable salt thereof decreases glycolysis in the mammal.
18. The method of clause 17, wherein the decrease of glycolysis comprises an inhibition of GAPDH activity.
19 The method of clause 18, wherein the inhibition of GAPDH activity is associated with a cancer cell.
20. A method of treating cancer, said method comprising the step of administering a compound and a therapeutic agent to a mammal, wherein the compound is a compound of the formula (I) or a pharmaceutically acceptable salt thereof:

wherein:
R1 is selected from C1-12 alkyl, C3-12 alkenyl, C3-12 alkynyl, C3-8 cycloalkyl, and heterocyclyl, each of which is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
R2 and R3 are the same or different and each is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino; and
R4 is —C(═O)R5, wherein R5 is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
or R4 is a non-steroidal anti-inflammatory drug (NSAID) moiety retaining its NSAID activity,
wherein the compound of the formula (I) or pharmaceutically acceptable salt and the therapeutic agent are effective in treating cancer in the mammal.
21. The method of clause 20, wherein the cancer is selected from the group consisting of breast cancer, lung cancer, prostate cancer, bone cancer, skin cancer, melanoma, pancreatic cancer, liver cancer, colon cancer, colorectal cancer, stomach cancer, esophageal cancer, nasopharyngeal cancer, thyroid cancer, ovarian cancer, bladder cancer, uterine cancer, multiple myeloma, leukemia, lymphoma, melanoma, sarcoma, nasopharyngeal cancer, kidney cancer, testicular cancer, brain cancer, Hodgkin's disease and non-Hodgkin's lymphoma.
22. The method of clause 20, wherein the therapeutic agent is tamoxifen.
23. The method of clause 21, wherein the cancer is breast cancer and wherein the breast cancer is an estrogen receptor negative (ER(−)) breast cancer.
24. The method of any one of clauses 20 to 23, wherein the cancer is located in an oxygenated region of a tumor.
25. The method of any one of clauses 20 to 23, wherein the cancer is located in a non-oxygenated region of a tumor.
26. The method of any one of clauses 1 to 25, wherein the compound of the formula (I) or pharmaceutically acceptable salt thereof releases HNO at physiological pH.
27. The method of any one of clauses 1 to 26, wherein R1 is optionally substituted C1-12 alkyl, optionally substituted C3-12 alkenyl, or optionally substituted C3-8 cycloalkyl.
28. The method of any one of clauses 1 to 27, wherein R2 and R3 are the same or different and each is hydrogen, C1-12 alkyl, aryl, or heteroaryl, each of which, other than hydrogen, is optionally substituted.
29. The method of any one of clauses 1 to 28, wherein R2 and R3 are hydrogen.
30. The method of any one of clauses 1 to 29, wherein R1 is optionally substituted C1-12 alkyl.
31. The method of any one of clauses 1 to 29, wherein R1 is optionally substituted C1-4 alkyl.
32. The method of any one of clauses 1 to 29, wherein R1 is isopropyl.
33. The method of any one of clauses 1 to 32, wherein R4 is —C(═O)R5, wherein R5 is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino
34. The method of any one of clauses 1 to 33, wherein R5 is an optionally substituted C1-12 alkyl
35. The method of any one of clauses 1 to 34, wherein the compound of formula (I) is

36. The method of any one of clauses 1 to 34, wherein R4 is an NSAID moiety retaining its NSAID activity
37. The method of clause 36, wherein said NSAID moiety is a moiety of an NSAID selected from the group consisting of aspirin, propionic acid derivatives, acetic acid derivatives, sulphonanilides, licofelone, enolic acid derivatives, fenamic acid derivatives, and selective COX-2 inhibitors
38. The method of clause 36, wherein the NSAID is selected from the group consisting of aspirin, ibuprofen, naproxen, fenoprofen, ketoprofen, flurbiprofen, oxaprozin, indomethacin, sulindac, etodolac, diclofenac, piroxicam, meloxicam, tenoxicam, droxicam, lomoxicam, isoxicam, mefenamic acid, meclofenamic acid, flufenamic acid, tolfenamic acid, celecoxicab, rofecoxib, valdecoxib, parecoxib, lumiracoxib, etoricoxib, nimesulide, licofenac, and mflumic acid
39. The method of any one of clauses 1 to 38, wherein the compound is selected from the group consisting of:

40. The method of any one of clauses 1 to 38, wherein the compound selected from the group consisting of:

wherein:
L is a linking group selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, aryl, arylalkyl, carbonyl, thiocarbonyl, iminocarbonyl, carboxyl, and carbamoyl;
R1 is selected from C1-12 alkyl, C3-12 alkenyl, C3-12 alkynyl, C3-8 cycloalkyl, and heterocyclyl, each of which is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino; and
R2 and R3 are the same or different and each is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
or a pharmaceutically acceptable salt of the compound
41. The method of any one of clauses 1 to 38, wherein the compound selected from the group consisting of:

wherein:
L is a linking group selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, aryl, arylalkyl, carbonyl, thiocarbonyl, iminocarbonyl, carboxyl, and carbamoyl;
R1 is selected from C1-12 alkyl, C3-12 alkenyl, C3-12 alkynyl, C3-8 cycloalkyl, and heterocyclyl, each of which is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino; and
R2 and R3 are the same or different and each is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
or a pharmaceutically acceptable salt of the compound.
42. The method of any one of clauses 1 to 41, wherein the NSAID is selected from the group consisting of aspirin, ibuprofen, and diclofenac.
43. The method of any one of clauses 1 to 38, wherein the compound is selected from the group consisting of:

44. The method of any one of clauses 1 to 38, wherein the NSAID is aspirin or salicylic acid.
45. The method of any one of clauses 1 to 38, wherein the compound or salt is:

46. A kit comprising a compound of the formula (I) or a pharmaceutically acceptable salt thereof:

and a therapeutic agent,
wherein:
R1 is selected from C1-12 alkyl, C3-12 alkenyl, C3-12 alkynyl, C3-8 cycloalkyl, and heterocyclyl, each of which is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
R2 and R3 are the same or different and each is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino; and
R4 is —C(═O)R5, wherein R5 is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl,
C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
or R4 is a non-steroidal anti-inflammatory drug (NSAID) moiety retaining its NSAID activity.
47. The kit of clause 46, wherein the therapeutic agent is tamoxifen.
48. A kit comprising a compound of the formula (I) or a pharmaceutically acceptable salt thereof:

and instructions for the detection of one or more thiols in a cellular protein,
wherein:
R1 is selected from C1-12 alkyl, C3-12 alkenyl, C3-12 alkynyl, C3-8 cycloalkyl, and heterocyclyl, each of which is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
R2 and R3 are the same or different and each is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino; and
R4 is —C(═O)R5, wherein R5 is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
or R4 is a non-steroidal anti-inflammatory drug (NSAID) moiety retaining its NSAID activity.
49. The kit of any one of clauses 46 to 48, wherein the compound of the formula (I) or pharmaceutically acceptable salt thereof releases HNO at physiological pH.
50. The kit of any one of clauses 46 to 49, wherein R1 is optionally substituted C1-12 alkyl, optionally substituted C3-12 alkenyl, or optionally substituted C3-8 cycloalkyl.
51. The kit of any one of clauses 46 to 50, wherein R2 and R3 are the same or different and each is hydrogen, C1-12 alkyl, aryl, or heteroaryl, each of which, other than hydrogen, is optionally substituted.
52. The kit of any one of clauses 46 to 51, wherein R2 and R3 are hydrogen.
53. The kit of any one of clauses 46 to 52, wherein R1 is optionally substituted C1-12 alkyl.
54. The kit of any one of clauses 46 to 52, wherein R1 is optionally substituted C1-4 alkyl.
55. The kit of any one of clauses 46 to 52, wherein R1 is isopropyl.
56. The kit of any one of clauses 46 to 55, wherein R4 is —C(═O)R5, wherein R5 is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino
57. The kit of any one of clauses 46 to 56, wherein R5 is an optionally substituted C1-12 alkyl
58. The kit of any one of clauses 46 to 57, wherein the compound of formula (I) is

59. The kit of any one of clauses 46 to 57, wherein R4 is an NSAID moiety retaining its NSAID activity
60. The kit of clause 59, wherein said NSAID moiety is a moiety of an NSAID selected from the group consisting of aspirin, propionic acid derivatives, acetic acid derivatives, sulphonanilides, licofelone, enolic acid derivatives, fenamic acid derivatives, and selective COX-2 inhibitors
61. The kit of clause 59, wherein the NSAID is selected from the group consisting of aspirin, ibuprofen, naproxen, fenoprofen, ketoprofen, flurbiprofen, oxaprozin, indomethacin, sulindac, etodolac, diclofenac, piroxicam, meloxicam, tenoxicam, droxicam, lomoxicam, isoxicam, mefenamic acid, meclofenamic acid, flufenamic acid, tolfenamic acid, celecoxicab, rofecoxib, valdecoxib, parecoxib, lumiracoxib, etoricoxib, nimesulide, licofenac, and niflumic acid
62. The kit of any one of clauses 46 to 61, wherein the compound is selected from the group consisting of:

63. The kit of any one of clauses 46 to 57, wherein the compound selected from the group consisting of:

wherein:
L is a linking group selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, aryl, arylalkyl, carbonyl, thiocarbonyl, iminocarbonyl, carboxyl, and carbamoyl;
R1 is selected from C1-12 alkyl, C3-12 alkenyl, C3-12 alkynyl, C3-8 cycloalkyl, and heterocyclyl, each of which is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino; and
R2 and R3 are the same or different and each is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
or a pharmaceutically acceptable salt of the compound
64. The kit of any one of clauses 46 to 63, wherein the compound selected from the group consisting of:

wherein:
L is a linking group selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, aryl, arylalkyl, carbonyl, thiocarbonyl, iminocarbonyl, carboxyl, and carbamoyl;
R1 is selected from C1-12 alkyl, C3-12 alkenyl, C3-12 alkynyl, C3-8 cycloalkyl, and heterocyclyl, each of which is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino; and
R2 and R3 are the same or different and each is selected from hydrogen, C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl, each of which, other than hydrogen, is optionally substituted with one or more moieties selected from the group consisting of halo, OH, CN, hydroxy-C1-12 alkyl, halo-C1-12 alkyl, amino-C1-12 alkyl, C1-12 alkoxy, aryloxy, C1-12 thioalkoxy, nitro, sulfonato, C1-12 acyl, C2-12 acyloxy, carboxyl, mercapto, C1-12 alkoxy-carbonyl, C1-12 alkoxy-carbonyloxy, amido, amino, C1-12 alkylamino, and di-C1-12 alkyl-amino;
or a pharmaceutically acceptable salt of the compound.
65. The kit of any one of clauses 46 to 64, wherein the NSAID is selected from the group consisting of aspirin, ibuprofen, and diclofenac.
66. The kit of any one of clauses 46 to 63, wherein the compound is selected from the group consisting of:

67. The kit of any one of clauses 46 to 63, wherein the NSAID is aspirin.
68. The kit of any one of clauses 46 to 63, wherein the compound or salt is:
